1. Field of the Invention
The present invention relates to a ceiling fan with a rotary blade surface light, and more particularly to a ceiling fan with a rotary blade surface light for flashing a light source of a light at a predetermined rotation position on a rotary blade.
2. Description of the Related Art
As means for circulating indoor air for comfortable air-conditioned environments, ceiling fans have been used that include a rotating blade placed near a ceiling and that circulate indoor air by the flow of air caused by rotation of the blade. In recent years, ceiling fans having a light including an integrated illumination light have been also used.
Utility Model Registration No. 3109730 discloses a ceiling fan with an illumination device in which a rotary blade having a light source therein and a rotation contact terminal that supplies electric power to the light source are mounted on a rotating shaft extending from a motor, and the rotary blade and the rotating shaft are connected by a flange.
Utility Model Registration No. 3110299 discloses a compact fan in which a fan unit including a blade is mounted on a rotating shaft of a drive motor protruding from a grip, a light emitter that emits light outward in a flashing manner is provided in the fan unit, and the light emitter is placed on the blade. The compact fan supplies electricity to the light emitter via the rotating shaft of the drive motor, and thus displays various light patterns forming multiple circles according to rotation of the blade, which has a strong visual stimulus.
Utility Model Registration No. 3111819 and Japanese Patent Laid-Open No. 2003-314487 also disclose a portable fan in which a light emitting member is placed on a blade or on a blade support, an operation state of the light emitting member is controlled by energization, and blades are rotated to display a pattern or an image on a moving locus of the light emitting member using an afterimage effect of eyes.
In Utility Model Registration No. 3109730, a light source of various types such as a light emitting diode or a fluorescent lamp can be used, but in any cases, the amount of heat corresponding to the input electric power is generated from the light source to increase the temperatures of the light source mounted on the rotary blade.
Light emitting diodes (LED) have been used for illumination because of characteristics thereof of low power consumption, long life, low heat generation, saving space, or the like, but most of high output type LEDs require radiating means such as a heatsink. Without proper radiation, the life and performance of the LED may be significantly shortened and impaired.
Utility Model Registration No. 3109730 does not disclose cooling of the light source and the rotary blade. When the capacity of the light source is small, the temperatures of the light and the rotary blade may be kept within a safe range by radiation from a rotary blade surface, but when the light source requires a larger illumination capacity, the amount of heat generated is increased, and the temperatures of the light and the rotary blade may exceed the safe range.
To solve this problem, radiating means of various types can be provided in incorporating a light source in the light source housing. As specific means for facilitating radiation, it is supposed that a light source is mounted on a printed circuit board using a metal plate having high heat conductivity, or a heatsink is further mounted.
However, in facilitating radiation by such means, a large surface area of a radiator is required for increasing convection to air and radiation efficiency, which increases the size of the light. When the size or structure of the light is restricted, electric power input to the light source needs to be reduced for a balance with radiation, which may prevent desired brightness from being obtained.
Utility Model Registration No. 3110299, Utility Model Registration No. 3111819, and Japanese Patent Laid-Open No. 2003-314487 describe examples flashing light emitting members. However, these examples are intended for displaying various visual light patterns with a portable fan rather than cooling the light emitting member, and cannot be applied to a ceiling fan having a blade surface light intended for illumination.